Repeating circuit interrupter



Sept. 1, 1970 K. H. DATE.

REPEATING CIRCUIT INTERRUPTER 2 Sheets-Sheet 1 Filed June 15, 1966INVENTOR. Kazuo H. Date Sept. 1, 1970 K. H. DATE REPEATING CIRCUITINTERRUPTER 2 Sheets-Sheet 2 Filed June 15, 1966 A R. 8 @J 0 1C N A rum,1 a r N 0 J M a 1-- I r W Llwlx mw w N w Z mfi m 0 mm H mm K V r B QM, 3L M QM, mN k Dm w I uh M w w %Q\ Q wk 0 R v N0 u o 3 ms 0 m in l my H@mm $0 an QQ m MN 0 \h as 0 Nu WW 9 k% MIN m m.

United States Patent O 3,526,735 REPEATIN G CIRCUIT INTERRUPTER KazuoHenry Date, South Milwaukee, Wis., assignor to McGraw-Edison Company,Milwaukee, Wis., a corporation of Delaware Filed June 15, 1966, Ser. No.557,660 Int. Cl. H01h 3/00 US. Cl. 200-153 7 Claims ABSTRACT OF THEDISCLOSURE An operating mechanism for a vacuum circuit interrupter isprovided in which an operating means moves between first and secondpositions in which the electrodes of the vacuum interrupter arerespectively closed and open. The operating means is held in its secondposition by the operating mechanism to prevent reclosing of theelectrodes until the operating mechanism releases the holding means. Theoperating mechanism and a closing means cooperate to reclose theelectrodes and charge a resilient opening means through a toggle linkagemeans. The linkage means is connected to the resilient means and theoperating means so that the mechanical lever advantage of the linkagemeans is utilized in charging the resilient means to thereby reduce theamount of force that must be applied to charge the resilient means.

This invention relates to repeating circuit interrupters and, moreparticularly, to an operating mechanism for repeating circuitinterrupters having vacuum current interrupting devices.

Because of the many characteristic differences. between interrupters ofthe vacuum type and those employing a dielectric medium, conventionaloperating mechanisms are not satisfactory in circuit breakers employingvacuum interrupters. For example, one such difference is the relativelyshort opening stroke characteristic of vacuum devices which introducesproblems of rapid deceleration and contact bounce. In addition, there isa greater tendency for the contacts in vacuum interrupters to weld shut,wherein means are required for impacting the contacts during an openingoperation. Further, vacuum interrupters are generally provided with butttype contacts requiring greater contact pressure than circuit breakershaving contacts with multiple points of engagement.

A primary object of the invention is to provide a circuit breakeroperating mechanism having specific application to vacuum type circuitinterrupters.

Another object of the invention is to provide means for decelerating themoving contact in vacuum circuit interrupters.

Yet another object of the invention is to provide means for preventingcontact bounce in vacuum type circuit interrupters.

A further object of the invention is to provide means for breaking weldsin the contact of a vacuum type circuit interrupter.

Yet another object of the invention is to provide a circuit breakeroperating mechanism capable of supplying relatively high contactpressure to the butt contacts of a vacuum circuit interrupter.

Still another object of the invention is to provide a vacuum circuitinterrupter having movable contact impacting means for weld breakingwith means for supporting the vacuum envelope and terminal bushingsindependently of the movable contact.

These and other objects and advantages of the instant invention willbecome more apparent from the detailed description thereof, taken withthe accompanying drawings in which:

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FIG. 1 is a side elevational view, with parts broken away, of a circuitbreaker incorporating the instant invention;

FIG. 2 is a fragmentary view of the circuit breaker illustrated in FIG.1; and

FIGS. 3, 4 and 5 show the circuit breaker operating mechanism accordingto the instant invention in its various operative positions.

Referring now to the drawings in greater detail, FIG. 1 shows apolyphase repeating circuit breaker having current interrupters 11 ofthe vacuum type. The circuit breaker 10 is provided with a metallicenclosure 12 having a cover 13 which supports porcelain terminalbushings 14 for connection to conductors (not shown). In additionconductors (also not shown) extend from the lower ends of bushings 14 toconnect with the movable and stationary electrodes or contacts 15 and16, respectively, of the vacuum circuit interrupters 11.

The details of the vacuum circuit interrupter 11 form no part of theinstant invention and, accordingly, will v not be discussed in detailfor the sake of brevity. For a more complete description of the vacuumcircuit interrupter, reference is made to co-pending application US.Pat. No. 3,280,286, issued to I ohn W. Ranheim on Oct. 18, 1966, andassigned to the assignee of the instant invention.

A suspension assembly 17 rigidly supports each of the vacuum interrupterassemblies 11 below the cover 13, and each assembly 17 includes anopen-ended rectangular bracket 18 which is suitably affixed at its topto the cover 13. A pair of insulating support rods 19 are secured to thelower surface of bracket 18 and extend downwardly therefrom. In additiona first support plate 20 is secured to the lower end of the insulatingrods 19 and in turn supports a second plurality of insulating rods 22which carry a second support plate 23 at their lower ends. The upper andlower ends of the vacuum interrupter 11 are rigidly affixed to thesupport plates 20 and 23, respectively. Because of the rigid manner inwhich the interrupters 1 1 are supported, it is possible during anopening operation, as will be discussed in greater detail hereinafter,to impact the movable electrodes 15 with a great deal of force to breakany welding that may exist with the stationary electrodes 16. This is incontrast to certain prior art circuit breakers where the vacuuminterrupters are part of or suspended from the porcelain insulatorswherein such impacting of the stationary contacts or electrodes is notpossible.

An operating rod 25 extends lengthwise of the housing 12 and beneath thecover 13 and is connected by pins 26 to the knee of a toggle linkage 27associated with each phase, and each of which comprises a first link 28and a second link 30. Each of the first links 28 is pivotally connectedat their other ends to fixed pins 31 and the other ends of the secondlinks 30- are pivotally connected to the upper end of an insulatingcontact rod 33 which extends downwardly into the interrupting assembly11 of each phase to engage the movable electrodes 15 so that saidcontacts in each phase may be simultaneously opened.

FIG. 2 shows in greater detail the connection between each toggle link30 and its contact rod 33 to include a stem 34 afiixed by a pin 35 in atelescoping relation to the upper end of the rod 33. Each stem 34extends upwardly from its rod 33 and into a sleeve 36 to which it isconnected by a pin 37 which extends through the stem 34 and into slots38 formed in the opposite side of sleeve 36. In addition, the upper endof each sleeve 36 is pivotally connected to its associated toggle link30 by a pin 39. A contact pressure spring 40 surrounds each stem 34 andextends between a cup-shaped member 42 mounted in an inverted relationat the upper end of the rod 33 and a washer 43 mounted at the lower endof the sleeve 36.

Switch opening energy for each of the movable electrodes is provided byan opening spring 45 affixed at one end by a pin 46 to the operating rodand at its other end to a pin 47 fixed to the casing 12. It will beappreciated that movement of the rod 25 towards the right, as viewed inFIG. 1, would charge the opening spring and straighten the togglelinkages 27 to thereby move the contact rods 33 downwardly to close themovable electrodes 15. On the other hand, when the rod 25 is releasedfor movement toward the left in FIG. 1 and under the in fiuence ofspring 45, the toggle linkages 27 will collapse to raise the rods 33 andthereby open the movable electrodes 15.

An operating mechanism 50, according to the instant invention, isdisposed in a metallic housing 51 suitably affixed adjacent one end ofthe enclosure 12. As seen in FIG. 1, the operating rod 25 extends fromthe enclosure 12 and into the housing 51 where it is coupled to theoperating mechanism 50. A control 53 for initiating the various openingand closing operations of the circuit breaker 10, is disposed within aseparate metallic housing and is electrically connected to the mechanismby a cable 54. As will be understood by those skilled in the art, manytypes of controls which are suitable for use with the circuit breaker 10are well known, and accordingly, control 53 will not be discussed indetail. For a complete description of a control capable of use with thedisclosed circuit breaker, reference is made to U.S. Pat. No. 3,100,854,issued to Richard E. Riebs on Aug. 13, 1963, and assigned to theassignee of the instant invention.

As seen in FIGS. 3-5, the operating mechanism 50 includes a first latchassembly 56 for holding the electrodes 15, 16 in a closed positionagainst the opening spring 45, a second latch assembly 57 for holdingthe contacts 15, 16 in an open position to prevent contact rebound and areset assembly 58 for resetting the first latch assembly 56 and forreleasing the second latch assembly 57.

A trip solenoid 62 is provided for releasing the first latch assembly 56so that the operating rod 25 is freed for movement to a switch openposition under the influence of opening spring 45. After a switchopening operation, a motor 64 is operative through a gear mechanism 65and a reclosing lever 66 to actuate the reset assembly 58.

The first latch assembly 56 includes a latch member 68 which ispivotally mounted about a fixed pin 70 and which is urged towardclockwise rotation and against a stop pin 71 by a small spring 72. Anintegral arm 74 extends outwardly from the latch member 68 and carries apin 75 at its outer end which normally lies in the path of the tripsolenoids plunger 77.

The first latch assembly 56 also includes a latch lever pivotallymounted intermediate its ends about a pin 81 carried by one end of alink 82 which in turn is pivotally mounted intermediate its ends on afixed shaft 84. A roller 86 is mounted at one end of latch lever 80 andcooperatively engages the latch 68 while the other end of lever 80 ispivotally connected to one end of a link 88. The other end of link 88 ispivotally connected to one arm of a bell crank 89 which is pivotallymounted about a fixed shaft 90 and whose other arm is pivotallyconnected to the operating rod 25.

It will be appreciated from the description thus far that when theelectrodes 15, 16 are in their closed position, as shown in FIG. 3, theopening spring 45 will be extended and will urge the operating rod 25toward the left to rotate the bell crank 89 and the latch lever 80counterclockwise. Such movement is prevented, however, by the latch 68which lies in the path of roller 86 to prevent rotation of the latchlever 80.

The second latch assembly 57 includes a latch crank 94 pivotally mountedon a fixed shaft 95 and having a latch surface 97 for cooperativelyengaging a pin 98 carried by the operating rod 25. A long link 100 isprovided for interconnecting the other arm of the latch crank 94 withthe other end of the link 82.

The reset assembly 58 includes a reset latch pivotally mounted aboutfixed shaft 106 and having a latch tip 108 engageable with a latch arm109 pivotally mounted on a second fixed shaft 110. In addition, theassembly 58 includes a reset lever 112 carried on a fixed shaft 113 anda first link 115 which couples the lever 112 to the free end of thelatch arm 109 and a second link 116 which couples the arm 109 and thelink 115 to the pin 81 carried by the latch lever 80.

When the operating assembly 50 is in its position shown in FIG. 3 theelectrodes 15, 16 are in their closed position and the opening spring 45is extended. Should the control assembly 53 sense the necessity for aswitch opening operation, it will cause the energization of the tripcoil 62 in a manner well known in the art. This causes the solenoidplunger 77 to move upwardly and impact the pin 75 carried by the latch68 and thereby to rotate the latch counterclockwise from its positionshown in FIG. 3 to its position shown in FIG. 4. This frees the latchlever 80 and the bell crank 89 for counterclockwise rotation about thepin 81 and shaft 90, respectively, as the opening spring 45 moves theoperating rod 25 toward the left, as viewed in FIGS. 3 and 4. Inaddition, this movement collapses the toggle links 27 associated witheach phase to move the sleeves 36 upwardly.

It will be recalled that when the electrodes 15, 16 are in their closedposition and the opening spring is extended, as seen in FIG. 3, the pin37 in the stem 34 is initially intermediate the ends of the slot 38formed in the sleeve 36. As a result, therefore, when the sleeve 36initially begins moving upwardly during a switch opening operation, thecontact rod 33 will remain in its switch closed position. After thesleeve 36 has moved upwardly a short distance, however, the slots 38will impact the pins 37 at a relatively high speed so that the impactforce will be sutficient to break any welding which may exist in theelectrodes 15, 16. It will be appreciated, too, that this initialopening movement of the sleeve 36 under the influence of opening spring45 will be aided by the contact pressure springs 40.

The operating mechanism 50 is able to impact the movable electrodes 15with a high opening force because each of the interrupters 11 isrelatively rigidly mounted between the plates 20 and 23 and by theinsulating support rods 19 and 22. This rigid mounting insures that therefractory portions of the interrupter 11 will not be unduly stressed bythe impacting force. Also because the movable electrodes 15 are mountedindependently of the terminal bushings 14, the latter will not besubjected to the impacting force.

As seen in FIGS. 3 and 4, the engagement between the latch arm 109 andthe reset latch 105 will hold the lever 82 inactive during the initialrotational movement of the latch lever 80 and the bell crank 89. As aresult, the latch crank 94 will also remain inactive so that the pin 98will engage the latch surface 97 when the operating rod 25 reaches itsfull switch-open position shown in FIG. 4. As a result, return movementof the operating rod 25 is prevented so that the movable electrodes 15are prevented from rebounding toward their closed positions.

After the operating rod 25 reaches its fully open position to rotate thebell crank 89 and the latch lever 80 counterclockwise, the left end ofthe latch lever 80 will engage the reset latch 105 to rotate the lattercounterclockwise against a small reset spring 120 as seen in FIG. 4.This releases the latch arm 109 so that the levers 82 and 112 are freeto pivot clockwise about their respective shafts 84 and 113 from theirpositions shown in FIG. 4 to their positions shown in FIG. 5. Thisrotational movement of the levers 82 and 112 may be brought about eitheras a result of their own weight or a small spring (not shown) may beprovided for this purpose.

As the lever 82 pivots, the pin 81, which rotatably supports the latchlever 80, will move the lever 80 downwardly and against a stop 121,whereupon the roller 86 will again be positioned below the latch 68. Inaddition,

clockwise pivotal movement of the lever 82 Will elevate the link 100 torotate the latch crank 94 counterclockwise to move the latch surfaceaway from the pin 98. This places the mechanism 50 in a reset positionin preparation for a reclosing operation.

Reclosing of the electrodes 15, 16 may be initiated in any manner wellknown in the art, such as, for example, by means of a limit switch 122positioned below the reset lever 112. When the mechanism 50 reaches itsreset position, shown in FIG. 5, the reset lever 112 will engage thelimit switch 122, thereby completing an energizing circuit to thereclosing motor 64 which, in turn, rotates the reclosing lever 66counterclockwise. As the reset lever 66 rotates, a roller 123 on itsfree end will engage the underside of the reset lever 112 to rotate thelatter counterclockwise, thereby producing clockwise rotation in thelatch arm 109 to move it into engagement with the latch 105. Also,because the roller 86 carried by the latch lever 80 is disposed belowthe latch member 68, the lever 80 will rotate clockwise about its pointof engagement with latch 68 to rotate the bell crank 89 clockwisethereby to extend the opening spring 45 and to reclose the movableelectrodes 15. In addition, as the latch lever 80 rotates, it will movethe pin 81 in a generally upward direction to produce counterclockwiserotation in lever 82 to thereby return the latch crank 94 to its initialposition shown in FIG. 3. In this manner the mechanism 50 is reset inpreparation for subsequent switch opening operation.

Should a tripping operation become necessary while the main electrodes15, 16 are being reclosed, solenoid coil 62 may be energized to rotatethe latch 68 and release the latch lever 80 for counterclockwiserotation to allow a switch opening operation even though the reclosinglever '66 is in its reclosing position.

Those skilled in the art will appreciate that the force necessary toextend the opening spring 45 and to compress the contact pressure spring40 will increase as the charging of these springs proceeds. In order toeliminate the necessity for providing an inordinately large motor 64,the springs 40 and 45 are coupled to the operating rod through thetoggle linkage mechanism 27. Since the leverage expected by the togglelinks 28 and increases as they approach their straight line position, agreater spring charging force will be available at the time when thesprings and require a greater force for charging. In this manner, arelatively smaller reclosing motor 64 may be employed than wouldnormally be necessary.

While only a single embodiment of the invention has been shown anddescribed, it is not intended to be limited thereby.

I claim:

1. In a circuit interrupter having a vacuum envelope and switch meansincluding a pair of electrodes having adjacent ends enclosed within saidenvelope, one of said electrodes being movable between open and closedpositions with the other electrodes, the combination comprising:

resilient switch opening means coupled to said movable electrode;

an operating mechanism including,

an operating means connected to said movable electrode and saidresilient switch opening means and having a first position wherein saidmovable electrode is in its closed position and said resilient switchopening means is charged and being movable to a second position by saidresilient means wherein said movable electrode is in its open position,

first means engaging said operating means for holding the operatingmeans in its first position, release means operable to free saidoperating means for movement from its first to its second position,

second means maintained in a normal position when said operating meansis in its first and second positions for engaging and holding theoperating means when the latter is in its second position,

third means coupled to said second means for moving the second means outof its normal position after the operating means and movable electrodeshave respectively moved to their second and open posi tions; and

switch closing means engaging said operating mechanism for returningsaid operating means and movable electrode to their respective first andclosed positions and returning said second means to its normal position.

2. The circuit interrupter set forth in claim 1 wherein said secondmeans is disengaged from said operating means when said operating meansis in its first position and engaged with said operating means when itis in its second position and the second means is in its normalposition.

3. The circuit interrupter set forth in claim 1 wherein said secondmeans comprises second latch means having a position in latchedengagement with said operating means when said operating means is in itssecond position and said second means is in its normal position.

4. The circuit interrupter set forth in claim 1 wherein:

said third means includes linkage means having a rigid condition andbeing connected to said second means for holding the second means in itsnormal position and for moving said second means out of its normalposition upon release of the linkage means from said rigid condition;and

fourth means having a position in engagement with said linkage means tohold the linkage means in its rigid condition and being disengageablefrom said linkage means by said operating mechanism to release saidlinkage means from its rigid condition after said movable electrodemoves to its open position.

5. The circuit interrupter set forth in claim 4 wherein said first meansis movable to a position in engagement with said fourth means todisengage the fourth means from said linkage means.

6. The circuit interru ter set forth in claim 1 wherein:

said third means includes linkage means connected to said second meansfor moving said second means out of its normal position; and

said second means comprises second latch means connected to said linkagemeans and being in latched engagement with said operating means whensaid operating means is in its second position and said second means isin its normal position, said second latch means being movable out oflatched engagement with said operating means when said second means ismoved out of its normal position by said linkage means.

7. The circuit interrupter set forth in claim 6 wherein:

said switch closing means has a position in engagement with said linkagemeans; said operating mechanism includes fourth means having engaged anddisengaged positions with the linkage means for releasably holding saidlinkage means; and

said linkage means is movable to a rigid condition in engagement withthe fourth means by said switch closing means, said linkage meansholding the second means in said normal position when in said rigidcondition, said linkage means being movable to a collapsed conditionwhen disengaged with the fourth means to move said second means out ofits normal position, said linkage means remaining in said collapsedcondition until returned to said rigid condition by the switch closingmeans.

References Cited UNITED STATES PATENTS 1,821,813 9/1931 Nickle.1,972,362 9/1934 Sorcnsen. 2,804,521 8/1957 Van Ryan et al. 33521XR(Other references on following page) UNITED 7 STATES PATENTS Frank.

Miller.

Frink et a1 335-77 X=R Peek et a1.

Stramowski 335-76 XR Date 335-76 Flurscheim et a1.

Roxburgh et a1.

8 998,580 7/1911 Horton 200-153 1,165,843 12/1915 Burnham 200-1502,945,110 7/1960 McCloud 200-150 5 ROBERT S. MACON, Primary Examiner US.Cl. X.R.

